1. Field of the Invention
This invention relates generally to medical instruments, and more particularly to a disposable, specialized medical syringe with evacuated plunger that is typically used to dispense liquid preparations or that is used in the collection of blood or other body fluids via a needle orifice. Still more particularly, the present invention relates to a disposable article, a medical syringe apparatus with evacuated plunger that permits a detachable needle hub, with attached needle or other medical sharps device, to be quickly and safely detached from the syringe barrel body after use and to be withdrawn into and encapsulated within the chamber of an evacuated plunger, all actions being accomplished in a safe manner with one hand. The disposable syringe with evacuated plunger of the present invention is easily manufactured through the mechanical assembly of individual parts.
A problem for doctors, nurses and other health care personnel who use or handle medical sharps devices is the accidental puncture of the skin by the needle. The problem can be very serious if the needle has been used. Potentially fatal diseases, such as hepatitis or Acquired Immune Deficiency Syndrome (AIDS), can be contracted if the needle has been used on an infected subject.
The needle used for medicinal liquid injections or in the collection of blood or other body fluids is typically covered with a removable sheath prior to and following use to prevent accidental contact, but the act of replacing the sheath after use can still result in accidental skin puncture. Also, if the sheath is not securely repositioned, the danger exists that personnel subsequently involved in disposal of the device may become injured by accidental puncture.
The disposable retractable needle syringe of the present invention offers a solution to these problems that can be performed with a simple one-handed operation.
2. Description of Related Art
U.S. Pat. No. 3,008,570 discloses the use of a removable cap for the purposes of enclosing and protecting a sterilized syringe in a transport.
Solutions that attempt to better protect the health care worker include that disclosed in U.S. Pat. No. 4,790,822. The '822 patent discloses a disposable syringe in which the needle can be first captured by the plunger and then withdrawn into the barrel in a position with the needle completely protected by the barrel. The plunger can then be broken off, leaving the broken end flush with the end of the barrel, so that the needle cannot be accidentally pushed out from the barrel and exposed.
U.S. Pat. No. 4,747,830 discloses a similar system with a plunger that can be broken off once the needle is retracted into the barrel. U.S. Pat. Nos. 4,692,156 and 4,643,200 disclose similar systems, used with a blood donor assembly, which allows retraction of a needle into a barrel.
U.S. Pat. No. 4,425,120 discloses a needle guard movable on the syringe barrel between an extended position in which the needle guard shields the needle and a retracted position in which the needle is exposed for use.
U.S. Pat. No. 4,816,022 discloses a syringe with a sliding cap for preventing accidental puncture. The '022 patent utilizes a nub and backseat for engagement of a nose-piece for securing the cap around the syringe for safety purposes. U.S. Pat. No. 4,840,619 discloses a syringe assembly that has a transport held in telescoping position over a syringe by flanges. Other and various means of sheathing or shielding a syringe are shown in the following U.S. Pat. Nos.: 4,738,663; 4,723,943; 4,666,435; 4,655,751; 4,639,249; 4,592,744; 4,356,822; 4,300,678; 3,976,069; 3,895,633; 3,107,785.
U.S. Pat. No. 4,826,483 discloses a non-reusable syringe with one-way movable position.
U.S. Pat. Nos. 5,000,736 and 5,125,898 to Kaufhold et al show disposable syringes with automatic needle retraction. The Kaufhold patents allow the used needle or other medical sharps device to be encapsulated within an evacuated plunger of a syringe, such encapsulation being accomplished through the rupture of specialized annular rings, and thus render the syringe apparatus safe for handling immediately after use and throughout subsequent disposal procedures, as well as rendering the syringe unsuitable for further use.
A disposable medical collection tube holder assembly with retractable needle is disclosed in United States Non-Provisional Patent Application Ser. No. 09/175,484 to Tripp et al. filed Oct. 20, 1998 and assigned to the same assignee as the current invention.